BilboroughShirley

Vinyl discs

Recommended Posts

Col just a question out of curiosity. When I had a turntable (A JVC years ago) it was common to place a small coin on the stylus to prevent skipping. Is there an ideal pressure?

Share this post


Link to post
Share on other sites

I wouldn't add any additional weight to a pickup arm beyond what the cartridge maker recommends.  If the weight is accurately set I would be looking for other causes of groove jumping.  Tightness in arm bearings, or even just a defective disk.  Question would be, is. It just jumping on this one disk or on most of the disks I play?  Even check the turntable with a spirit level to make sure everything is even.  Some arms also have adjustment for lateral tension.  I forget the proper name for it.

 

Might also check if the deck is well isolated from feedback vibrations from the speaker system.

  • Like 1

Share this post


Link to post
Share on other sites
On 24/03/2018 at 2:39 PM, Brew said:

Col just a question out of curiosity. When I had a turntable (A JVC years ago) it was common to place a small coin on the stylus to prevent skipping. Is there an ideal pressure?

 

Only just spotted this.  The short answer is that there is no single 'ideal' weight.  All cartridges and styli come with a recommended 'tracking weight', or 'stylus downforce'.  It is recommended by the manufacturer and is I think partly related to the 'compliance' ( the stiffness or otherwise of the stylus suspension) of the cartridge and maybe also the stylus 'profile'. ( Some are conical, some elliptical and some just plain strange...)  A properly set up stylus/tonearm combination should track a decent record without issue. 

On the old Dansettes and similar, this was all factory set and suited the standard 'TC8' stylus.  Some other players may only have a stylus downforce adjustment and maybe adjustable 'bias force'.

 

Skipping can be caused by damage to the grooves, allowing the stylus to 'skip' sideways and miss part of the music, or to keep following the same bit of groove over and over. This can't really be fixed, though I have sort of done it by putting a bit of candle wax over the 'skip' and letting the stylus 'cut', a path through that.  But then you hear it.  Some skips are caused by something sticking to the surface of the record and this can often be felt with a finger and carefully flicked off by a  ( finger .. not 6" ...) nail.  The mind boggles at what such 'adhesions' might be, but I'd recommend trying not to sneeze on your records...  :blink:  If the tonearm has adjustable 'Bias' this can cause skipping and mistracking if incorrectly adjusted.

 

Adding a coin is a solution, but not ideal.  It is likely increasing the tracking force hugely which will quickly damage the record, or the stylus.  Better to fix the original problem.  Sometimes, the travel of the tonearm across the record might be a bit 'tight' at some point for some reason ( a sticky bearing, a trapped tonearm wire, or a dragging Bias weight cord) This will cause sticking at the same point on each record and the only cure is to I.D. the problem and fix it.

 

In the early days of vinyl some pick ups were tracking at tens of grams.  By the 60s and 70's some people were trying to track records at much less than a gram.  These days, most cartridges track somewhere around 1.5 to 2 grams.

Set it too heavy and it will damage record and stylus.  Set it too light and it will 'mis- track' by bouncing about in the groove rather than sitting securely and properly tracing it.  This will cause audible distortion and record damage.

 

When you get into the realm of 'posh' cartridges which can cost anything from  a few tens of £s up to £5k or more, it is always worth experimenting by adjusting the stylus force a bit either side of the recommended figure. Roughly speaking, a little heavier gives more bass, lighter gives a bit less.  The ideal is to find the 'sweet spot', where that individual cartridge seems to track happily and sounds 'right'.

 

With more sophisticated tonearms there are lots of other potential adjustments, such as stylus 'azimuth', 'stylus rake angle'  etc.  Then there's the issue of matching the cartridge 'compliance ' ( springiness) to the 'effective' mass of the tonearm.

 

I'm going to stop now.. but trust me, whole books have been written about this stuff and some people have even read them...  :laugh:

The 'easy' version.

https://www.henleyaudio.co.uk/cartridge-installation

The 'lunatic' fringe..

http://www.theabsolutesound.com/articles/setting-up-a-phono-cartridge/

 

Col

 

 

  • Like 2

Share this post


Link to post
Share on other sites

Well, thanks for that Col. I've always been curious but too lazy to research it. I wonder if a laser reader is possible 'ala CD style.

Share this post


Link to post
Share on other sites

Anything is possible, Brew.  I've never heard of any kind of laser reader for Lps, but then I must admit I am a bit behind the times these days.  :rolleyes:

  • Like 1

Share this post


Link to post
Share on other sites

It's been done Brew.  I can't recall the name of the company but I'll soon track it down.  Also a year or so back there was a cartridge which I think used a laser to transmit the stylus movement to an optical pick up, though I can't recall the claimed benefits.

 

Edit.  The company I recall, at least 10 years ago, was 'Finial'.  It looks now as if a Japanese Co. called ELP is selling laser turntables.

 

Lots of sites listed here.:  https://www.google.co.uk/search?q=Laser+Turntable&ie=utf-8&oe=utf-8&client=firefox-b-ab&gfe_rd=cr&dcr=0&ei=-c7TWpDEDerv8AfE_peIAw

 

Optical Cartridge here:  https://www.whathifi.com/news/worlds-first-optical-phono-cartridge-to-go-sale-ps6250

 

Col

Share this post


Link to post
Share on other sites

P.S.  The thing that constantly delights me about vinyl, is that it can achieve quite staggeringly good reproduction.  Low surface noise, great clarity and frequency response, but with a 'live' and 'real' sound which with CD always seems to be just a bit 'distant and detached'.  I don't subscribe to the usual media tripe about 'warm' sounding etc.  It sounds right.. and so right that the odd slight pop or click doesn't detract.

 

Vinyl is innefficient.  It costs megabucks to do right and eventually your record and stylus wear out.  It reminds me of Steam locos.  They too are high maintenance, expensive and ultmately inefficient.

But Oh my!... they are pleasing!!

 

Vinyl is beset with problems.  It is after all an electro/mechanical system in which a tiny diamond is dragged 'kicking and screaming' through a 'canyon' of vinyl.  The 'wiggling' of the stylus moves a little coil of wire relative to a set of magnets. ( Moving Coil or MC cartridge), or vice versa ( Moving Magnet or MM cartridge) and this tiny signal then has to be amplified many times in order to provide a  'Line Level' signal which can then be fed into an amplifier. What's more, the original music signal is deliberately altered to cut bass and boost treble, which produces a groove which is easier for a stylus to trace and takes up less space on a record.  This process must be completely and exactly reversed electrically, to produce listenable music.

Also, the turntable has to rotate consistently at the right speed, unaffected by 'stylus drag' (which may or may not actually exist), mains electrics issues/variations etc.

There must be no 'break through' of motor noise and no susceptibility to the music from the speakers 'feeding back' through the turntable.  Also the turntable must be sufficiently isolated from other extraneous noises and vibrations such as passing traffic, footfall etc.

The tonearm must be very free to move both laterally and vertically, but without any trace of slackness in its bearings, which will cause vibrations and tracking errors.  All tonearms have natural resonances, by virtue of their length. These must be suppressed.. somehow..

It's a bloody hopeless task really, but I love the way that 60+ years of development has led to something wonderful.

 

And all above said. I cut my teeth on juke boxes and Dansettes.

 

Col

  • Like 2

Share this post


Link to post
Share on other sites

Damn, I thought I'd had an original idea and would be on my way to a fortune. Ah well, back to the drawing board, at least I don't have to drag grannies radiogram up all those stairs to the dragons den.

I read your 'lunatic' link... wow... just wow...$15000 for a stylus! and some serious OCD to with it. With that amount of attention to detail, If they measure the tone arm angle to three decimal places of a degree I'm surprised there's no mention of frequency variation in the electrical supply, or are they DC motors?

  • Like 1

Share this post


Link to post
Share on other sites

Thanks for that interesting summary of what makes vinyl tick, Col.  The issue of bass compression was well explained.  I knew something like that went on but I had never truly understood it so tended to leave it alone.  When you think about it it is amazing that we get the great sound that we do.  I'm glad to have lived through such an era.  A bit like the steam engine illustration you used.  I was never much into railway steam engine type stuff but I'm glad to have ridden on one to Skeggy a time or two.

  • Like 1

Share this post


Link to post
Share on other sites

Interesting couple of posts, Col. I didn't realize how much there is to it, and I'm never too old to learn something new about an old subject.

Good posting.

  • Like 1

Share this post


Link to post
Share on other sites

I've forgotten almost all I ever knew about vinyl records except insofar as how robust the vinyl is.

 

A tonearm pressure of only a couple of grams will exert a force of many tonnes per square inch (or centimetre) on the record groove when the contact area of the stylus tip is considered.

  • Like 1

Share this post


Link to post
Share on other sites
10 hours ago, loppylugs said:

Thanks for that interesting summary of what makes vinyl tick, Col.  The issue of bass compression was well explained.  I knew something like that went on but I had never truly understood it so tended to leave it alone.  When you think about it it is amazing that we get the great sound that we do.  I'm glad to have lived through such an era.  A bit like the steam engine illustration you used.  I was never much into railway steam engine type stuff but I'm glad to have ridden on one to Skeggy a time or two.

 

Hi Dave,

The process is generally called 'phono equalisation' or EQ. It is why most amplifiers 'back in the day' had a specific input labelled 'phono'. This input had a 'phono EQ' circuit inside to 'do the business' and plugging straight from pick up to any other input would produce a very quiet, tinkly sound with no bass. So, apart from knowing to use the dedicated 'phono' input, most of us were oblivious to 'phono EQ' issues.  And of course with Dansettes etc., everything was wired together in one box so it wasn't an issue.

As far as I know, this sort of electrical 'fiddling' with the signal has existed since electrical recording was introduced around 1926.  Bass notes produce bigger groove 'excursions', which are both harder for a stylus to trace, and also take up more space on a record side.  So the bass cut and treble boost are introduced electonically at the record 'cutting' stage and must be reversed electronically by a 'phono pre-amp' or 'EQ stage', somewhere between the pick up and the amplifier. 

It seems that pre-vinyl, in the 78 era, companies tended to use their own EQ, but sometime post WW2 the Recording Industry Association of America, or RIAA 'curve' was introduced to standardise the process.  I believe there have been revised RIAA standards since, and then some engineers use slight variations on it to get a sound they want, but at least in theory, every 'phono EQ' stage should do, and sound, the same.

These days, most amplifiers do not have a dedicated 'phono' input and so you need to use a separate 'Phono Stage'/'Phono pre-amp' between the record player and the amp.  These can be had from about £50 up to 'How b****y much!!!!?'.  I use an all valve one made by Esoteric Audio Research (EAR) and designed by well known valve designer and audio lunatic Tim De Paravicini. Cost me £450ish  20+ years ago and now sells for around £1400, but you can pay much, much more.

There are even more issues, involving 'step up' transformers etc., when you get to fancy ( and expensive) moving coil cartridges which have very low signal output, but I won't go there... :)

 

Col

 

Share this post


Link to post
Share on other sites
11 hours ago, Brew said:

Damn, I thought I'd had an original idea and would be on my way to a fortune. Ah well, back to the drawing board, at least I don't have to drag grannies radiogram up all those stairs to the dragons den.

I read your 'lunatic' link... wow... just wow...$15000 for a stylus! and some serious OCD to with it. With that amount of attention to detail, If they measure the tone arm angle to three decimal places of a degree I'm surprised there's no mention of frequency variation in the electrical supply, or are they DC motors?

 

Hi Brew,

Yep.. people can get OCD about pretty much anything I suppose...  I try to limit my audio obsession to leave a bit of time for listening to music....  ;)

 

Now.  Electricity supply..  Maybe worth starting with a quick summary of turntable drive systems: The object is to drive the platter consistently at the correct speed, with zero variation ( wow and flutter)and with zero 'breakthrough' noise from the motor or bearing.

 

The main divide is between belt drive ( using either an AC, or DC motor) and 'direct drive', using a motor whose central spindle is directly below the platter, so that the platter is effectively a flywheel driven by the motor.  Both have their supporters and detractors.  Direct drive is the basis of the classic Technics 1200 series 'DJ decks' as it has very fast start up, and is very robust.  They were largely dismissed by the 'hi fi' community for years, but the newer Technics are now gaining acceptance.

 

Belt drive is probably most common and is represented by  Linn, Michell, Rega, SME, Pink Triangle/Funk Firm, Roksan, Project, Nottingham Analogue and countless others. Again though, many variations of multiple belt/motor systems,.... belt drive to a 'sub platter', belt around the platter rim, free standing motor, etc., plus 'suspended' ( Linn) 'inverted suspended' (Michell) and non suspended types.  I'll come back to this.

 

There is a sort of intermediate, usually called 'idler drive'.  In this format, a motor drives a spindle,which in turn drives a rubber 'idler wheel', which drives against the inside of the platter.  The old Dansettes used this principle, as did the classic Garrards (301/401) many of which are still in use and sounding amazing. Thorens used a slight further variation in which a small belt sits between the spindle and the idler. A classic 1960s Thorens TD 124 is a thing of beauty.

 

Much attention is paid to the motor in belt drive designs.  AC, as you know depends upon the frequency of the mains for its speed.  Simple motor power supplies are at the mercy of the mains and can also introduce 'cogging' effects, but Linn and others have long since introduced fancy 'off board' power supplies which seek to solve this by using electronics to 're-generate' a constant AC signal at the correct frequency for the motor.  The Linn supplies also apply a high voltage at start up which then drops back in operation to minimise transmission of motor effects via the belt to the platter.  As you'd expect, these boxes of tricks are far from cheap and a whole industry has developed offering cheaper/'better' alternatives.

 

As you also know, DC motors vary speed according to voltage.  They generally tend to have fewer adverse effects on sound, and so long as they can be fed a constant voltage, tend to sound more natural to these ears.  Numerous companies produce whole decks, or just 'after market' conversions, using DC motors with 'fancy' power supplies.  My Michell deck was originally designed with a fixed AC motor, which was later made 'free standing' and later still DC.

Mine has a 'servo' power supply system which uses some sort of electrical feedback to constantly monitor and correct speed.  Works for me!

 

Long ago I thought that maybe some sort of 'falling weight' mechanical system, similar to some pendulum clock drives, might work, by eliminating motors and electricity from the drive system.  Seems it also has been thought about by others..  'Nothing new under the Sun' !!

 

Col

  • Like 2

Share this post


Link to post
Share on other sites

Now you come to mention it Col.  I remember that first decent amp of mine.  Rogers Cadet III had a little plug in cartridge.  Two of them actually.  One for magnetic, and one for ceramic or other crystal type pickup cartridges.  You plugged in whichever matched your cartridge and you were all set.  Makes sense now.

Share this post


Link to post
Share on other sites

I had a Cadet amp for a while Dave.  I think mine was a II. It also had the little phono plug in module.

  • Like 2

Share this post


Link to post
Share on other sites

Does the Epi and vox give you a Beatle sound Ian?

  • Like 1

Share this post


Link to post
Share on other sites

Called in the Sally Army cafe in Bulwell today & a woman bought a "Supremes" LP all for .................50p !

Ooooohh   Baby Love, my baby love..............where's carni !

  • Like 2

Share this post


Link to post
Share on other sites
9 minutes ago, catfan said:

  Baby Love, my baby love..

 

I'm missin' ya,  ooh missed kissin' ya.:biggrin:

Haha, already watched Eastenders. One eye on NS and one eye on Casuality catch up at the moment.

  • Like 1

Share this post


Link to post
Share on other sites

Just giving this a spin on the old Gerrard before bed.

 

EYj-H98XkAA2Opg?format=jpg&name=small

Share this post


Link to post
Share on other sites

I suspect that might be Garrard Red...

 

Nice vid here:  All is revealed..

 

 

  • Like 1
  • Upvote 1

Share this post


Link to post
Share on other sites

Only managed one minute & thirty seven seconds DJ absolutely fantastic, very very interesting, made me appreciate being the chosen few not allowed to join you in isolation, boots on, crack on, keep the country moving. 

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...